Transcript Plasma Membrane

Plasma Membrane
Plasma Membrane
Structure
 Phospholipid bi-layer
Structure
 Phosphate Head – Hydrophilic
 Lipid Tail – Hydrophobic
 Glycoprotein/Glycolipids – Cell markers
 Carrier Protein – Passive and Active
Structure
Carbohydrate cell
markers
Proteins
Floating Mosaic
Phospholipid molecules
Function of the Plasma
Membrane
 - selectively permeable membrane
 - allows for communication between cells
 - provides the cell with a specific “marker”
Plasma Membrane
 Construction of the Cell Membrane Learning Ac - Flash Player Installation
Carrier Protein
 Passive Channel – Leakage channel
 Active Channel – Open and close to let
larger molecules through

- Uses Cellular energy
(ATP)
 Channel Protein
Particle Theory
 1. All matter is made of particles
 2. The particles are in constant motion
(Kinetic motion of particles)
 3. The closer the particles are together,
the greater the attractiveness between
them.
Particle Theory
 Solids – definite shape and volume
 Liquids – definite volume but indefinite
shape
 Gases – indefinite shape and volume
 Matter
Cellular Transport
 Passive Transport – use no cellular
energy
 A) Diffusion
 B) Osmosis
 C) Facilitated Diffusion
A. Diffusion
 - Movement of particles from an area of
High concentration to an area of Low
concentration
 - Particles will move until they are evenly
distributed in an Equilibrium
 - Particles continue random movement,
but it has no affect on the equilibrium
 Diffusion
B. Osmosis
 - special diffusion where water passes
through a selectively permeable
membrane from an area of High
concentration to an area of Low
concentration
 Osmosis
 Osmosis II
C. Facilitated Diffusion
 - special diffusion that is made faster by
using Passive Channels (leakage
channels)
 - can result in a conformational change in
the shape of the protein.
 Facilitative Diffusion
 Facilitated Diffusion II
 Facilitated Diffusion III
Try these:
 1. The plasma membrane consists of ___ layers.
 2. The molecules that make up the plasma membrane
are called ______
 3. The phosphate heads like water and are called
______.
 4. The lipid tails don’t like water and are called ______.
 5. Special protein molecules called _____ are found
throughout the plasma membrane.
 6. Cell markers called _______ are attached to the top
of these protein molecules.
 7. The Particle Theory states that all matter is made up
of tiny particles and that they are in _________.
 8. Cells need to move materials in and out to maintain
a state of balance between what is inside and outside.
This balance is called _______
 9. Cells move materials in and out in 2 ways.
___________ and ___________
 10. ________transport doesn’t require the cell to
expend any energy.
 11. ________ transport requires the cell to use some of
it’s own energy stored in _____
 12. There are 3 types of Passive Transport ________,
_________ and __________.
 13. Movement of any particles from H to L is called
________.
 14. Movement of water molecules from H to L is called
________.
 15. Diffusion of particles that are helped by carrier
protein is called __________.
Review of Passive
Transport
 Passive Transport
Environments that Cells
might find themselves in:
 A) Hypotonic Solutions – greater concentration
of water OUTSIDE the cell
 B) Hypertonic Solutions – greater
concentration of water INSIDE the cell
 C) Isotonic Solutions – even concentrations of
water inside and outside the cell
How will cells react in
each??
 Animal cells
 Hypotonic Solution
 - water moves into the cell (osmosis), the
cell swells, and may burst (Cytolysis)
 Hypotonic Solution
How will cells react in
each?
 Animal cells
 Hypertonic – water moves from inside
out and the cell shrivels and dehydrates
 Hypertonic
How will cells react in
each?
 Animal cells
 Isotonic – water moves in and out of the
cell at the same rate (Random movement)
 Isotonic
Another look:

Solutions
What about plant cells?
 Hypotonic – water moves in and Turgor
Pressure in the cell increases.
What about plant cells?
 Hypertonic – water moves out of the cell
and turgor pressure drops

- the plasma membrane pulls
away from the cell wall and the cell wilts.
 Plasmolysis
What about plant cells?
 Isotonic – water moves in and out at the
same rate.
Another look:
Cellular Traffic
 Active Transport (uses ATP)
 A) Endocytosis
 B) Exocytosis
 C) Movement against the “concentration
gradient”.
Cellular Traffic
 A) Endocytosis – movement of large particles
into a cell packaged in vesicles . The cell uses
energy stored in ATP
 i) Phagocytosis  - cell engulfs a large food particle by wrapping
it’s cytoplasmic arms around the particle
 Phagocytosis
Cellular Traffic
 i) Pinocytosis – cell engulfs a smaller
particle or water droplet into the cell by
indenting the plasma membrane. The cell
uses energy stored in ATP
 Pinocytosis
 Pinocytosis 2
Cellular Traffic
 B) Exocytosis – excreting materials from
a cell packaged in vesicles. The cell uses
energy stored in ATP.
 Exocytosis
 Exocytosis 2
Cellular Traffic
 C) Movement against the Concentration
Gradient (L to H)
 Particles are drawn against the concentration
gradient using active channels that open and
close using cellular energy
 L to H
 L-H
Cellular Transport Review
 Thirst Reflex
 Passive Transport
 Environments
 Drag and Drop Cell membrane
Homeostasis
 All these examples of cellular traffic are
designed to help the cell maintain a state
of balance between the inside and the
outside of the cell.